Found in northern Siskiyou and Modoc counties and in south central Oregon, this intergrade was once considered a unique subspecies: Thamnophis elegans biscutatus - Klamath Gartersnake.
More pictures of this intergrade snake can be viewed here.

Not Dangerous (Non-poisonous) - This snake does not have venom that is dangerous to most humans.

Gartersnakes have toxins in their saliva which can be deadly to their prey and their bite might produce an unpleasant reaction in humans, but they are not considered dangerous to humans.

Size

Thamnophis elegans measures 18 - 43 inches in length (46 - 109 cm).

Appearance

A medium-sized slender snake with a head barely wider than the neck and keeled dorsal scales.

Some scale averages: Average of 8 upper labial scales, occasionally 7, scales 6 and 7 are enlarged, higher than wide. Average of 10 lower labial scales. The front and rear pair of chin shields are equal in length. The internasals are wider than long and not pointed in front. Average scale count at mid-body is 21, rarely 19.

Color and Pattern

Ground color is a dark olive-brown or black with no red markings.
There are
3 well-defined light stripes on the back and sides:
The dorsal stripe is yellow, orange, or white.
The lateral stripes may be paler. Underside is pale with few markings, and is sometimes darker in the center.

Active in daylight. Chiefly terrestrial - not as dependant on water as other gartersnake species, but more likely to be found near water.

Defense

If frightened when picked up, this snake will often strike repeatedly and release cloacal contents.

When frightened, this species will sometimes seek refuge in vegetation or ground cover, but it will also crawl quickly into water and swim away from trouble.

Diet

Western Terrestrial Gartersnakes - Thamnophis elegans - eat a wide range of prey (among the widest of any snake species - Rossmann, et al. 1996.) The prey depends on the size of the snake (large snakes tend to eat larger prey, small snakes can only eat smaller prey) and what prey is available. Populations found on the humid North Coast where slugs are abundant are genetically predisposed to eat slugs, while populations in dryer areas where slugs are less common refuse to eat slugs when they are offered. (Rossmann, et al. 1996.)

Diet includes: invertebrates such as slugs, leeches, snails, and earthworms; fish; amphibians - tadpoles, frogs, (and probably salamanders); snakes and lizards;
birds; and small mammals such as mice and voles (and bats as you can see in the pictures above.)

At high elevations in the Sierra Nevada, Mountain Gartersnakes rely almost exclusively on amphibians for food, mostly Sierran Treefrogs.

In California, the subspecies Thamnophis elegans elegans - Mountain Gartersnake, is found throughout the Sierra Nevada Mountains, through most of the northern part of the state except for the outer Coast Ranges south at least as far as Mt. St. Helena. There is an isolated population in the San Bernardino Mountains.
The subspecies ranges out of the state north into Oregon and to the edge of northern Nevada.

Most range maps showing subspecies of T. elegans, show T. e. elegans occurring in the Central Valley near Lodi. Previously I changed my maps to show T. e. terrestris there based on the one bright red snake from Lodi seen above, but discussions with a herpetologist in that area have convinced me that they are T. e. elegans. It's likely that the wild-caught Lodi specimen was transported there.

The species Thamnophis elegans - Western Terrestrial Gartersnake, ranges widely from the California coast north through most of northern California, Oregon, Washington, Idaho and Montana, into Canada, including Vancouver Island, British Columbia, Alberta and Saskatchewan, and east into the states of Wyoming, Colorado, Utah, Arizona and New Mexico and just barely making it into South Dakota, Nebraska, and Oklahoma. Many isolated populations exist, including those in the San Bernardino Mountains and one in Baja California Norte, Mexico (the San Pedro Martir Gartersnake.)

Elevational Range

The species Thamnophis elegans - Western Terrestrial Gartersnake, occurs from sea level to 13,100 ft. (3,990 m) in elevation in Colorado. (Stebbins, 2003)

Notes on Taxonomy

T. e. vagrans intergrades withT. e. elegans in northeast California in Modoc and eastern Siskiyou counties and in south central Oregon (this snake was formerly classified as the subspecies Thamnophis elegans biscutatus - Klamath Gartersnake. Intergrades with T. e. elegans also occur along the southern and southeastern edge of the Sierras.

Rossman, Ford, and Seigel (1996) emphasize that a detailed study of geographic variation throughout the range of Thamnophis elegans is badly needed.

Bronikowski and Arnold (2001, Copeia 2001:508-513) found several clades within T. elegans that do not always follow the subspecies boundaries, and concluded that there was no support for the race terrestris. Presumably, the former T. e. terrestris snakes become T. e. elegans.

Not known to be threatened, but gartersnakes have been negatively impacted by competition with introduced bullfrogs and non-native fish in some areas. High-altitude populations of this snake may decline if populations of high-altitude frogs continue to decline.

Wright, Albert Hazen & Anna Allen Wright. Handbook of Snakes of the United States and Canada. Cornell University Press, 1957.

Conservation Status

The following status listings are copied from the April 2018 Special Animals List and the 2017 Endangered and Threatened Animals List, both of which are published by the California Department of Fish and Wildlife.

If no status is listed here, the animal is not included on either CDFW list. This most likely indicates that there are no serious conservation concerns for the animal. To find out more about an animal's status, you can go to the NatureServe and IUCN websites to check their rankings.